Rigid sleeve fan guard



Sept. 1963 .1. v. MILITELLO 3,402,882

7 I RIGID SLEEVE PAN GUARD Filed Oct. 4, 1966 2 Sheets-Sheet l I N VEN TOR.

JAMES v. MILITELLO 24 2 MJ Z vQJ/L ATTORNEYS P 1968 J. v. MILITELLO 3,402,882

RIGID SLEEVE FAN GUARD Filed Oct. 4, 1966 2 Sheets-Sheet 2 2! 22 4 48 q g; 4 .5? 5: Z; 1

4 s3 39 3 44 as INVENTOR.

JAMES V. MILITELLO ATTORNEYS United States Patent 3,402,882 RIGID SLEEVE FAN GUARD James V. Militello, Buffalo, N.Y., assignor to American Allsafe Co., Buffalo, N.Y., a corporation of New York Filed Oct. 4, 1966, Ser. No. 584,165

9 Claims. (Cl. 230275) ABSTRACT OF THE DISCLOSURE A rigid sleeve fan guard includes an impervious tubular sleeve surrounding a rigid fan cage and formed from a plastic sheet to provide overlapping ends fastened to compress the sleeve around the cage periphery. The sleeve is provided with inwardly open channels along its front and rear ends to compressively receive the outer peripheral raw edges of front and rear foraminous lastic face guards, and with front and rear annular end flanges projecting outwardly from such channels and of greater inside diameter than that of the meeting edges of such front and rear channels and a substantially deeper central channel surrounding the fan blades, to produce a venturi shape.

This invention relates to a rigid sleeve fan guard to envelope the rigid openwork metal cage surrounding the blades of an electric fan, the fan guard protecting against bodily contact with the revolving fan blades and stopping objects from being drawn into the zone of action of the fan blades.

An important object of the present invention is to provide such a rigid sleeve fan guard which adequately protects against bodily contact with the front, rear and peripheral portions of the fan blades.

Another object is to provide such a rigid sleeve fan guard which is attractive in appearance and which, in particular, is rendered delicate in appearance through the use of transparent, translucent, or opaque sheet plastic or other light weight sheet material for the rigid sleeve.

Another object is to provide such a fan guard which is adapted for diflFerent size fans.

Another object is to provide such a fan guard in which the parts are secured in stressed relation to one another and to the cage to prevent the production of noise in response to the action of the fan.

Another object is to provide such a fan guard which not only concentrates the direction of flow of the air from the fan to the zone in front of the blades by virtue of the enveloping rigid sleeve, but which also tends, by virtue of a venturi shape of the sleeve, to further concentrate the discharge of the fan and to recirculate a large body of air adjacent the fan thereby to secure comfort either by direct blast or by gentle but massive air movement as may be preferred.

Another object is to provide such a fan guard which is light in weight and low in cost and which can be readily attached to the fan by the use of simple tools and by one having little mechanical skill.

Other objects and advantages of the invention will be apparent from the following description and drawings in which:

FIG. 1 is a side elevationual view of an electric fan and cage illustrating the inventive rigid sleeve fan guard mounted thereon and showing, for clarity of illustration, the fan blades and shaft in broken lines; FIG. 2 is a transverse vertical sectional view taken generally on line 22 of FIG. 1; FIG. 3 is a longitudinal sectional view taken generally on line 3-3 of FIG. 1; FIG. 4 is a vertical transverse section view taken on line 4-4 of FIG. 1; FIG. 5 is a fragmentary view similar to FIG. 3 on an enlarged scale and illustrating in detail the fan guard mounted on the rigid openwork metal cage, and FIG. 6

3,402,882 Patented Sept. 24, 1968 is greatly enlarged fragmentary sectional view taken generally on line 66 of FIG. 2.

The fan protected by the fan guard forming the subject of the present invention can be of various forms and is shown as having a base 10* pivotally supporting, as indicated at 11 an electric motor housing 12 having the usual drive shaft 13 and airplane propeller type fan blades 14, for the purpose of clarity of illustration, are shown in broken lines. These fan blades 14 in a conventional table fan are enclosed in a metal cage 15 made of wire or the like and secured to the end head 16 of the electric motor housing 12 by screws 18 or the like.

The fan cage 15 is shown as comprising a large central wire ring 20 flanked by smaller coaxial, axially spaced outer rings 21, 22, the latter being on the side of the fan remote from the motor housing 12. In a parallel plane forward of this ring 22 of the fan is a much smaller concentric hub ring 23. These rings 20, 21, 22 and 23 are joined together, and to the motor housing 12 by a series, shown as being six in number, of wire front spoke members 24 each of which comprises a front arm 25 having its inner end secured to the small hub ring 2'3 and projecting radially outwardly therefrom; an arching portion 26 each forming a continuation of the outer end of the corresponding spoke 24 and secured to each of the outer rings 20, 21 and 22; a rear spoke member 28 forming a continuation of the end of each of four of the arching portions 26 and extending radially inwardly therefrom; and a bridging portion 29 connecting the companion inner ends of each pair of rear spoke members 28, these bridge portions 29 each including an offset 30' through which the shank of the corresponding attaching screw 18 extends.

The fan guard of the present invention includes a tubular sleeve compressively embracing the periphery of the fan cage 15 and securely held against displacement therefrom in a manner to avoid rattling. This sleeve is imperfor-ate and made of a strip of light weight sheet material and preferably a transparent, translucent or opaque organic plastic, By the use of such sheet material the sleeve is very light in weight and easy to apply to the fan cage 15. A feature of the invention lies in the strip of light weight sheet material forming the sleeve 35 having overlapping peripheral ends 36 and 38, the extent to which these ends overlap being determined by the outside diameter of the fan cage 15, this permitting the use of the same length of plastic sheet material for fan cages of different sizes. The length of sheet material forming the sleeve 35 is characterized by its having a large rounding central channel portion 39 which extends the full length of the strip of sheet material and the concave side or face 40 of which, when applied to the fan cage 15, receives and compressively engages at its center the large central ring 20 of the fan cage so as to hold the sleeve in centered relation with the fan cage. This compressive engagement of the sleeve 35 with this ring 20 is obtained by drawing the overlapping ends 36 and 38 of the strip of sheet material firmly together so as to contract the sleeve 35 into compressive engagement with the largest central ring 20 of the fan cage and thereafter maintain this compressive relation by the use of suitable fastening means. Such fastening means can, of course, be of wide variety of forms, including stretchable bands (not shown) enveloping the entire sleeve 35, but are shown as being in the form of simple staples 42 passing through the overlapping portions 36 and 38. Such staples can be such as are used in an office stapling machine (not shown) to secure papers together since the plastic strips forming the sleeve 35 are not required to have great thickness.

A feature of the invention resides in the provision of a pair of front and rear annular inwardly opening channel portions 43 formed in the sleeve 35 along the front and rear ends of the large central channel 39 to provide inwardly facing concave faces or annular channels 44. It will be noted that annular inwardly projecting ribs 45 are provided by the joined edges of each of the front and rear channel portions 43 and the substantially deeper central channel portion 39. in addition, the front edge of the front channel 43 is continued forwardly in the form of an annular cylindrical forwardly projecting flange 46 and the rear edge of the rear channel portion 43 is continued rearwardly in the form of an identical annular cylindrical rearwardly projecting flange 46, these flanges serving not only to rigidify the sleeve 35 but also to extend its axial length both in increasing its protecting effect so far as the fan blades 14 are concerned, and also to render the discharge of air by these fan blades highly directional, that is, directly forward. This is achieved not merely by virtue of the sleeve 35 preventing peripheral discharge of air from the ends of the blades 14 but also by virtue of the venturi shape produced by the cross sectional shape of the sleeve 35, the internal diameter of the front and rear flanges 46 being substantially greater than the internal diameter of the ribs 45 produced, between the central channel portion 39 and each of the front and rear channel portions 43. It will be noted that annular inwardly projecting ribs 48 are provided by the joined edges of each of the front and rear channel portions 43 and their front and rear flanges 4d.

The fan is protected at its front and rear by front and rear face guards t), 51. Preferably each of these face guards is also made of sheet organic plastic or light weight material, but of forarninous form, having a large open face area provided by holes 52 of uniform size and shape provided uniformly over the entire face thereof so as to produce an undressed indented or raw edge 53 extending completely around each face guard. These raw edges 53 are of a size slightly greater than the internal diameters of the front and rear inwardly opening concave faces 44 and are inserted in these channels after the fasteners 42 have been applied to hold the sleeve 35 in compressive relation with the fan cage 15. The front and rear face guards 5t), 51 are applied by being dished into into concavo-convex form so as to reduce the diameter of their edge portions 53 to be of smaller size than the inwardly projecting ribs 48 provided at the front and rear, respectively of the front and rear channel portions 43. After being so contracted, the raw edges 53 of the front and rear face guards 58, 51 can be positioned in line with the front and rear channels or concave faces 44 and then permitted to expand to be compressively held in these channels.

In order to be capable of being fitted around the bearing for the fan shaft 13 in the end head 16 of the motor housing 12, the rear face guard 51 is additionally provided with a radial split 55 from its raw edge 53 to a circular opening 55 at its center, the latter being large enough to accommodate this hearing extremity of the motor end head 16.

In addition to this, it is desirable to provide a positive fastening means for securing the front and rear face guards 50, 51 to the fan cage so that they cannot be removed by individuals who might seek to alter the effect of the fan by removing the front and rear face guards. To this end simple wire clips 59 can be provided which are generally of U-shaped form and the legs which can be passed through the forarninous face guard and brought into embracing relation with the front spokes at the front of the fan cage and with the rear spoke members 28 at the rear of the fan cage. Following this, by means of a pair of pliers (not shown) used to insert these U-shaped staples or fasteners, the legs of the wire clips 59 can be pinched together so as to provide a series of positive fasteners which not only unit the front and rear face guards 50, 51 to the front and rear face portions or spokes of the fan guard 15 but also serve to additionally stress these face guards so as to reduce the likelihood of development of noise through movement of any parts of the fan guard with reference to one another or with reference to the fan cage 15.

From the foregoing it will be seen that the present invention provides a very low cost, light weight fan guard which can readily be assembled to a standard fan cage to provide a high degree of safety against accident and which is not likely to create any noise in response to the vibrations of the fan by virtue of all of the parts of the fan guard being held in compressive relation with one another as well as with the fan cage.

Iclairn:

1. A guard for an electric fan having a base, a motor housing supported by said base and a rigid fan cage secured to said motor housing, said fan guard comprising a tubular sleeve of sheet material surrounding and in pressure contact with the periphery of said cage and provided along its front and rear ends with inwardly opening front and rear channels, front and rear face guards in the form of foraminous flexible sheet material generally conforming to the cross sectional shape of said sleeve and having edge portions in radial pressure contact with the interiors of said channels, said pressure contact of said sleeve with said face guards minimizing noise from the vibration of these parts and holding these parts in assembled relation with one another with said cage.

2. A guard as set forth in claim 1 wherein said tubular sleeve is imperforate and composed of a light-weight organic sheet plastic.

3. A guard as set forth in claim 1 wherein said tubular sleeve has overlapping peripheal ends and fastening means securing together said overlapping ends to maintain said pressure contact between said sleeve and the periphery of said cage.

4. A guard as set forth in claim 1 wherein each of said face guards is composed of a light-weight flexible organic plastic in sheet form.

5. A guard as set forth in claim 4 wherein the openings providing the foraminous sheet of each face guard are of uniform size and shape and extend over the entire area thereof to provide raw edges at the margins of said sheets.

6. A guard as set forth in claim 1 wherein said sleeve has a central annular portion arranged between said front and rear channels and adapted to house the periphery of said cage in compressive relation therewith.

7. A guard as set forth in claim 6 wherein said sleeve is imperforate and includes front and rear annular edge flanges projecting outwardly and of an inside diameter greater than the inside diameter of the meeting edges of said front and rear channels with said central portion.

8. A guard as set forth in claim 1 wherein said cage has a larger diameter peripheral portion at its center and said sleeve has a central inwardly opening annular channel arranged between and substantially deeper than said front and rear channels and adapted to house said larger diameter center peripheral portion of said cage in compressive relation therewith.

9. A guard as set forth in claim 1 additionally including fasteners extending through and holding each of said foraminous face guards in pressure contact with said cage.

References Cited UNITED STATES PATENTS 1,809,583 6/1931 Cook 230275 1,971,332 8/1934 Cook 230-275 2,036,478 4/1936 Hoff 230-275 2,668,523 2/1954 Lamb 230-275 ROBERT M. WALKER, Primary Examiner. 

